I made this as directed, egg yolk and all, and it is just a beautiful frosting! I, of course, had to adjust the measurements of the juices a bit to get the frosting to the perfect consistency (no recipe for frosting can be precise, so should not be criticized if more or less powdered sugar or liquid needs to be added). This is a light, fluffy, citrus frosting that was the perfect choice to frost Rainbow Citrus Cake, also from this site.

Reviewer:

This was easy and tasty. As I do with all frosting recipes, I doubled it. I omitted the egg yolk and added in addition to the juice some orange flavored liquor. This has a nice subtle flavor. I will definately make this again.

Reviewer:

Awesome!!! Since I was not making this for my family, I did not use the egg yolk. I am not sure of the purpose of the yolk - I have never made a frosting that called for one. I also only used 3 cups of sugar and with the lack of the the moisture from the yolk, I ended up adding in more lemon and orange juice. It was perfect for piping on my mini cupcakes.

Reviewer:

Nice frosting! This is very much what you make of it. Do you want something really stiff? Put in lots of sugar and less juice. Do you want something more liquidy? More juice, less sugar.
To do this, I got the butter/zest/salt base down (omitted the yolk, like other reviewers said), then took turns adding a cup of sugar and a few teaspoons of juice. This let me bulk up in volume while keeping a good consistency, and when it came time to spread it on the cake, I got it as stiff/liquidy as I wanted. I loved being able to control it like that.
I pretty much doubled the recipe. That got me more than enough icing for a three-layer 9-inch round cake.

Reviewer:

Quite tasty, although I recommend doubling the recipe. I did and needed it all to frost a 2-layer 9" cake. Use fresh zest because it really adds great flavour. I also added it splash of orange extract.